Converter-bottom for bottom-blow steel making process

ABSTRACT

An improved converter-bottom for a bottom-blow steel making furnace including water cooling coils in the refractory of the bottom of the furnace surrounding the concentric tube gas and oxygen injectors and water spray units surrounding the concentric tube gas and oxygen injectors where water is provided through the trunnions of the converter unit and sent by conduit to the spray means and to the water coils. The water spray units may be used alone underneath the converter in an alternate form of the invention.

United States Patent 1191 Chang 1 Mar. 25, 1975 CONVERTER-BOTTOM FOR BOTTOM-BLOW STEEL MAKING PROCESS [75] Inventor: Yi-Chung Chang, Murrysville, Pa.

[73] Assignee: Berry Metal Company, Harmony,

221 Filed: Mar. 26, 1973 211 App]. No.: 344,811

[52] U.S. Cl. 266/35,}66/41 [51] Int. Cl. C2lc 5/48 [58] Field of Search 75/60; 266/32, 35, 36 P, 266/41 [56] References Cited UNITED STATES PATENTS 129,512 7/1872 Baker 266/41 327,421 9/1885 Witherow 266/35 519,218 5/1894 741,505 10/1903 1,338,655 4/1920 2,333,654 11/1943 3,330,645 7/1967 3,386,720 6/1968 3,608,880 9/1971 Gombert 266/41 3,706,549 12/1972 Knuppel et a1. 266/35 FOREIGN PATENTS OR APPLICATIONS 124,118 4/1959 U.S.S.R 266/35 64,977 12/1955 France 266/41 3,274 8/1878 United Kingdom 266/36 P 45-29728 9/1970 Japan 266/35 Primary Examiner-Gerald A. Dost Attorney, Agent, or F irm-Richard J Myers [57] ABSTRACT An improved converter-bottom for a bottom-blow steel making furnace including water cooling coils in the refractory of the bottom of the furnace surrounding the concentric tube gas and oxygen injectors and water spray units surrounding the concentric tube gas and oxygen injectors where water is provided through the trunnions of the converter unit and sent by conduit to the spray means and to the water coils. The water spray units may be used alone underneath the converter in an alternate form of the invention 13 Claims, 13 Drawing Figures CONVERTER-BOTTOM FOR BOTTOM-BLOW STEEL MAKING PROCESS BACKGROUND OF THE INVENTION 1'. Field of the Invention This invention relates to the construction'and opera tion of the bottom-blow steel making converter and in particular relates to the construction of the lower or bottom portion of the furnace in order to improve the life of the bottom portion of the furnace as well as to make it safer for use.

2. DESCRIPTION OF THE PRIOR ART The process of refining hot metal (pig iron) into steel by blowing either air or air enriched with oxygen from underneath the steel bath in a converter is a wellknown process. Typical examples are the acid- Bessemer and the Thomas processes. When pure oxygen gas is used for blowing the steel bath from the bottom, the life of the tuyeres becomes intolerably short and frequent replacement of the converter-bottom becomes necessary. In recent years, an innovation has been made in the design of the injection tuyere and the method of injecting oxygen. Generally speaking, concentric-tube injectors are adapted with the inner tube for injecting oxygen gas and the surrounding annular space of the second tube for simultaneously injecting a protective gas or vapor. By so doing, the life of the converter-bottom can be lengthened to approximately 200 heats vs. approximately 400 heats for the life of the refractory lining of the'converter shell. In other words, for the life of the converter shell lining, two converterbottoms are required. It becomes very clear that further improvement of the converter-bottom is needed to make it last as long as the shell lining. Toward this end, the applicant's inventive design has been conceived and overcomes the aforementioned difficulties.

SUMMARY OF THE INVENTION The inventive design disclosed herein has for its primary object the improvement of the bottom of the bottom-blow steel making converter which results in improved length of life of the converter and reduces greatly or eliminates entirely the danger of any steam explosion that could occur when using water for cooling of the furnace.

It is a further purpose of this invention to provide for water spray cooling around the concentric gas and oxygen injectors or tuyere-like structures, the water spray being between a spray shield on the refractory and the concentric gas tubing of gas and oxygen.

It is a further purpose of this invention to provide for cooling the bottom refractory throughthe metallic bottom plate by high speed water jets and to provide a shroud for the water spray means as well as the gas supply means against any spillings or ejections of hot metal and slag from the converter, and confining the splash of spray-water.

further object of the invention is to provide for introduction of the cooling water through conduits in the trunnions of the converter that leadto the bottom portion of the converter. Still another object of this invention is to provide for means for feeding'oxygen and the shielding gas from their supply lines into the concentric-tube injectors.

It is also another advantage of this invention to provide for cooling coils in the refractory in the bottom of the converter furnace that may have a common inlet line with the spray apparatus forcooling the gas and oxygen injectors.

A further object of the invention isto provide for in troduction of the water through conduits in the trunnions of the converter that lead to the bottom portion of the converter. A further advantage of the invention provides for a layout of the gas and oxygen concentric injector tubes designed to flow the same amount of gas and whereby the concentric tubes are evenly distributed with reference to the effective cross-sectional area of the converter-bottom. An alternate layout of injector tubes in this invention eliminates some tubes in the bottom of the furnace to give the advantage of pouring of the molten material without back flow of melt into the injectors when the converter is in thetilted position.

Still another advantage of this invention is to provide for a concentric-tube gas and oxygen injector which includes a connector block with one entrance hole for the protective gas or vapor and another entrance hole for the oxygen gas. Still another object of this invention is to provide for a tapered collar arrangement which is placed on top of the steel spray shield around the injector tip, thereby separating the supply of water for the spray cooler from the supply of water for the imbedded cooling coils to further reduce any hazards of steam explosion. Another advantage of this invention is to provide for tubular spray shields that may be constructed out of steel tubes such as steel boiler tubes and rolled into the bottom plate of the bottom portion of the furnace for improved ease of construction of the furnace.

These and other objects and advantages will become apparent from reference to the following description. the appended claims and attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a general view illustrating the exterior of a steel refining converter of thebottom-blow type;

FIG. 2 is an upright cross-sectional view of the converter-bottom portion of the type of converter referred to in FIG. 1;

FIG. 2A is an alternate form of the invention illustrating the bottom portion of the converter;

FIG. 2B is illustrative of another form of oxygen and shielding gas distribution shown in FIGS. 2 and 2A;

FIG. 2C is still another illustration of oxygen and shielding gas distribution arrangement shown in FIG. 2;

FIG. 2D is still another illustration of oxygen and shielding gas distribution arrangement shown in FIG. 2;,

FIG. 3 is a schematic diagram of an arrangement of the gas injectors of the concentric type of oxygen and protective gas;

FIG. 3A is an alternate arrangement of injectors shown in FIG. 3;

FIG. 4 shows a cross-section of one type of construction of concentric-tube protective gas and oxygen injector;

FIG. 4A is illustrative of the plumbing or conduit circuitry of the injector shown in FIG. 4;

FIG. 5 shows an enlarged view of the arrangement of the concentric tube injector in reference to the spray shield referred to in FIG. 2;

FIG. 6 shows a construction of the spray shield in reference to the furnace bottom plate which is of modified form over that illustrated in FIGS. 2 and 5; and

F IG. 7 illustrates anotherconstruction of the feeder block.

DESCRIPTION OF THE PREFERRED With reference now to the drawings and in particular with reference to FIG. 1, there is shown a bottom-blow steel making converter 2 which includes a top converter shell lining 4 and a converter bottom part 6 from which depends the fuel storage tank containing the protective gas such as methane, the oxygen storage tank, and the water sump. all within the lower section 8. The converter furnace 2 is pivotally mounted by its trunnions 10 on trunnion ground-supported standards orupright members 12. The source of methane for the converter is introduced by inlet line 14 and the source of oxygen gas is introduced into the converter by inlet line 16 and water as a coolant is introduced from a source into the converter by line 18.

With attention now directed to FIGS. 2 and 5, the. converter 2 is shown in exposed cross-section where the fluid conducting lines l4, l6 and 18 having passed through the upright standards 12 pass into the trunnions l and from there into the bottom 6 which is provided with a fuel storage tank 20 which stores the protective gas of methane from line 14 on the right side of the convertenThe bottom 6 of the converter is also provided below the fuel tank with an oxygen storage tank 22 which communicates with the oxygen gas sup-. ply line 16 and is also provided with a water sump 24 that communicates with and receives the water from the water spray apparatus, to be explained later, andg from the drain line 220 that drains water from the water-cooling coils, to be explained below. The line 22a is in communication with the water inlet line 18. By this arrangement water introduced into the water-cooling coils and into the spraying apparatus is allowed to fallinto the 'water sump through the grid arrangement 24a and then the water in the sump by means of a-pump (not shown) may be recirculated back into the line 18 by way of the water source' (not shown). It will be appreciated that various water circulating systems may be used in order to get water into the water-cooling coils 26 and the water spraying apparatus 28. a

The converter-bottom 6 is provided with a steel shel ring 30 forming the upright cylindrical wall of the bottom and has attached thereto a horizontal steel bottom plate 32. A water spray shield 34 encapsulates the two concentric-tube methane and oxygen gas injectors 36, the fueltank ,20, the oxygen tank 22 and the water sump 24. The water-cooling coils 26 are imbedded in the rammed refractory brick or material 38 around the concentric-tube gas injectors 36 and within the steel cylindrical jacket 30. The water spraying apparatus 28 surrounding each of the injectors 36 comprises a plurality of upright elongated tubes 40 having a pluralityof openings 42 therein to allow the water to spray out around the concentric injectors 36 and within the spray shield structure 34, as shown in FIG. 2 or the modified form of tubular or cylindrical spray shield 34a, as shown in FIG. 5. Each concentric-tube gas injector includes an inner or central tube 36a bearing the oxygen from the oxygen tank '22. The oxygen tube 36a has an upper orifice 36b which communicates with the interior of the bottom of the furnace for introducing the oxygen directly into the melting area 43 in the furnace. The injector 36 is provided with an outer concentric tube 36c which defines an annular methane gas passage communicating with the fuel tannk 20 and with a methane gas orifice 3611 in the bottom'of the furnace which communicates with the melting area 43. The protective fluid, such as methane gas, is injected into the converter in the form of an enveloping mantle around the oxygen stream because of the construction of each injector 36. Thus it is seen that the injectors are kept cool as is the bottom of the furnace by the water flowing in the water-cooling coils and spraying from the spraying apparatus back into the water sump. In the embodiments shown in FIGS. 2 and 5 water is supplied from a common source to both the coils and the spray apparatus under the spray shield, however, the supply of cooling water to these two types of spray and coil cooling systems can be served not only by a single piping system using a common control valve 44, as shown schematically in FIG. 2, but in the alternative these two cooling systems could be served by separate pipings. It

is to be noted that a tapered copper collar 46 is placed on top of each steel spray shield portion over the spray area as shown in both FIGS. 2 and 5. Each tapered copper collar surrounds an injector tip of each injector 36 as its orifices 36b and 36c at the juncture with the interior area 43 of the converter. The upper portions of the cooling coils 26 do not extend above the juncture of the water spray shields with the collars 46 to insure that the cooling coils and the spray apparatus provide a suffi- 7 rior 43 of the converter. This is to insure that the water cannot come in contact with the hot interior of the converter and, therefore, avoiding any danger of steam exp iqa With attention now directed to an alternate form of the invention as shown in FIG. 2A the converterbottomis provided with a steel shell ring 30' forming the'upright cylindrical wall of the bottom and has attached thereto a horizontal steel bottom plate 32. A water spray shroud 34 encapsulates the bottom plate 32 and the spray means 28, the shielding gas distributor 20',the oxygen distributor 22 and the water sump 24'. Each concentric-tube gas injector includes an inner or central tube 36a bearing the oxygen from the oxygen distributor 22. The oxygen tube 36a has an upper orifice 36b which communicates with the interior of the bottom of the converter for introducing oxygen directly into the melting area 43 in the converter. The injector 36 is provided with an outer concentrictube 36c (FIG. 4) which defines an annular methane gas passage communicating with the shielding gas distributor 20' and with a methane gas orifice 36d in the bottom of the furnace which communicates with the melting area 43.

The converter-bottom of FIG. 2A is provided with the cooling water spray apparatus 28 which communicates with water inlet line 18', and a water sump 24' under the spray water apparatus to collect the falling water. By this arrangement water introduced into the spraying apparatus is allowed to fall into the water sump through the grid arrangement 24a and-then the water in the sump by means of a pump (not shown) may be recirculated back into the line 18' by way of the m sasnurss .t 99!. shswn v backing layer is the metallic bottom plate. During the usage of the converter, the working layer is gradually consumed andthe life of the bottom ends when the working layer becomes too thin. In my inventive design of FIG. 2A the bottom refractory consists of the working layer only without a backing layer. The working layer is directly supported by a metallic bottom plate through which heat is extracted from the bottom refractory by spray cooling. The lower than usual temperature of working refractory prolongs the service life of the bottom by slowing down the erosion of the refractory. Omission of the highly insulative backing layer is to facilitate heat extraction. Thus, it is the main purpose of the design of FIG. 2A to control the tempera ture of the upper surface of the refractory at or only slightly above the melting point of the steel which is in direct contact with the upper surface of the refractory bottom. This is done by measuring the temperature of the bottom refractory by means of a series of thermocouples or temperature sensors 70 or the like with electrical lead wires 71 to a source of electrical power (not shown), the sensors 70 being located at strategic points of the refractory as shown in FIG. 28. Based on the re sult of temperature measurement the cooling rate is regulated to achieve the proper temperature at the upper contacting surface of the refractory.

FIG. 3 is illustrative of a layout of the gas injectors 36. In general, the gas injectors are designed here to flow the same amount of gas and these injectors are evenly distributed with reference to the effective crosssectional area of the converter bottom 6. One injector 36 is located at the center of the converter bottom and being larger than the rest it is designated as 37. Radiating out from this enlarged injector 37 in radial line and on a plurality of concentric annular paths are the plurality of smaller injectors or tuyeres 36. A common methane gas line 37a is common to each set of radially lined methane tubes 360 so that methane gas from methane gas inlet line l4,reaches the methane conduit portion of each injector. Each set of radially aligned methane conduits are fed: from the central methane conduit of the central injector 37. Similarly, oxygen is supplied to each of theoxygen conduits 36a of each of the injectors 36 by a common oxygen gas distributor line 39,which communicates with the oxygen conduit 36a of the main'injector 37. The main injector 37 has communication with the methane inlet line 14 and the oxygen gas inlet line 16 and, consequently, a plurality of radially extending oxygen distribution lines 39 and methane distribution lines 37a provide all of the smaller injectors 36 with the protective gas and the oxygen. The oxygen distribution lines 39 in FIG. 3 are shown by solid line and the methane distribution line 37a is shown by dash lines in FIG. 3.

FIG. 3A is illustrative of a modified layout of the gas injectors 36 shown in FIG. 3. The piping system for the gases is located under the converter-bottom. Radiating out from the reservoirs in radial lines are the plurality of the injectors 36. The oxygen distribution lines 39 in FIG. 3A are shown by solid lines and the methane distribution lines 37a is shown by dash lines.

Layout of the concentric-tube injectors in the bottom plane may follow one of several patterns. The arrangement could be either-symmetrical with respect to the center of the circular bottom as shown in FIG. 3 or unsymmetrical with the injectors located in one or several particular regions for the purposes of improved circulation and ease of tilting the converter as shown in FIG.

3A. Some of the layout patterns are already described in the patent literature. The bottom of my invention is compatible with any of these layout patterns and I do not wish to limit to any particular layout pattern for the oxygen injectors.

There are two general ways to feed the oxygen and the shielding gas into the concentric-tube injectors. The first method is shown in FIG. 2 or FIG. 2A. The oxygen supply 16 of FIG. 2 is piped to the oxygen distributor 22 whereto the inner tube (oxygen tube) of all the injectors is connected. Similarly, the shielding gas supply 14 is piped to the shielding gas distributor 20, whereto the outer tube (the shielding gas tube) of all the injectors is connected. The arrangement is featured by the topology that all the oxygen tubes pass through the shielding gas distributor. It is possible to combine the lower wall of the distributor with the upper wall of distributor 22 as is shown in FIG. 2C. This construction can be further extended to a double windbox arrangement 25 as shown in FIG. 2D for distributing gas for a conventional converter-bottom without using any water cooling means.

A second method of distributing the gases is to use individual feeder blocks of constructions shown in FIG. 4 and FIG. 7 for each injector.

FIG. 4 illustrates a construction of the concentrictube gas injector 36 which comprises a feeder connector block 48 with a shielding gas or methane entrance hole or cavity 52 for the protective gas or vapor and another entrance hole or cavity 50 for the oxygen gas. Two holes, one inner or reduced hole 54 communicates with oxygen inlet 50 and is at gradual right angles to it, and another enlarged hole 56 above hole 54 and at right angles to entrance hole 52 communicates with hole 52. The feeder block 48 is then connected with the injector 36 such that the outer concentric tube 360 communicates with opening 56 and the inner oxygen tube.36a communicates with the opening 54 and the feeder block 48 may then be connected with the respective oxygen and methane lines as shown in FIG. 4A.

FIG. 7 illustrates another construction of the feeder block. It is constructed by passing a smaller tube 61 tthrough a hole in the wall of a larger tube 62. At the said hole, tube 61 is welded to the wall of tube 62. Tube 62 may be tapered as shown in FIG. 7 but is not necessary. Both tubes 61 and 62 may be bent to facilitate the piping arrangement. The telescoped end 64 and the separate ends 65 and 66 may be threaded or be provided with other connecting means for making connections with the concentric-tube injector and the gas supply lines.

FIG. 6 shows a modified construction of the spray shield 58 in reference to the steel bottom plate 32. The spray shield arrangement 58 comprises a plurality of tubular spray shields 60 construction of, for instance. steel boiler tubes and rolled into the bottom plate 32 to provide for a plurality of housing areas 62 for the gas injectors 36 and their respective water spray tubes 40. Space is provided between the tubes 60 for rammed refractory brick or material 38.

Thus, what is provided herein is a novel and inventive arrangement of water cooling in the form of imbedded cooling coils and/or water spray structure to prolong the service life of the converter-bottom of the bottomblow steel making process. By limiting the cooling coils to locations well below the working refractory. the danger of direct contact with molten steel is virtually removed when using such a cooling arrangement. Also, by using fairly hot water as the cooling medium, steam explosion will not be likely to occur.

It will be noted that the spray arrangement operates under low or no pressure and is vented to the atmosphere and, therefore, there is no danger of steam explosion due to delivery of high pressurized cooling spray. Also, the cooling medium in the cooling coils is under low pressure, also to avoid any explosion due to high steam pressure.

The foregoing description and drawings merely illustrate and explain the invention and the invention is not limited thereto, except insofar as the appended claims are so limited, as those skilled in the art who have the disclosure before them will be able to make modifications and variations therein without departing from the,

scope of the invention. What is claimed is: 1. In a bottom-blow steel making converter, a converter-bottom comprising:

a metal shell side wall means,

a metal bottom wall,

gas injector means extending upright through the bottom wall,

rammed refractory material between the injector means and the side wall means and forming a bottom surface below a converter melting area up to which extends a top of the injector means to provide gaseous communication of the gas within the injector means into the interior of the melting area.

coolant spray and metal shield means between the refractory material and the injector means,

coolant spray means extending in between the shield means and the injector means and being below the converter bottom surface below the melting area, said spray means spraying the coolant under low pressure in the area of the injector means attendant to cooling the gases to be emitted from the injector means, and

cooling means between the injector means and the metal side wall means in the rammed refractory material and spaced substantially below the bottom surface of the melting area so as not to come in contact with the melting area,

said metal shield means being spaced from and disposed about said spray means and said injector means, and

a tapered and top annular metal collar means having a reduced upper end adjacent the bottom surface of said refractory material and an enlarged lower end disposed on saidmetal shield means, said refractory material including portions surrounding and covering the upper'reduced end of said metal collar means from the converter melting area, said metal collar means being disposed about the top of said injector means whereby said metal collar means and said metal shield means effectively cool the top of said injector means upon operation of said spray means during use of said converter.

2. The invention according to claim 1, and

said injector means comprising a plurality of injectors within the rammed refractory material, each injector including a pair of concentric inner and outer tubes defining a central inner passageway communicating with the interior of the melting area and an outer annular passageway surrounding the central passageway and communicating with the interior of the melting area.

3. The invention according to claim 2, and

said outer passageway providing for a conduit of a protective gas such as methane and the inner passageway providing a conduit for oxygen gas.

4. The invention according to claim 2, and

said injector comprising a connecting block to a source of protective gas for the outer tube and to a source of oxygen gas for the inner tube,

saidblock having a first inlet opening for the protective gas and a second inlet opening for the oxygen gas.

said block having a firstenlarged aperture transverse to and communicating with the first opening and connecting with outer tube, and

said block having a second reduced aperture transverse to and communicating with second opening and connecting with the inner tube.

5. The invention according to claim 1, and

said metal shield means being spaced substantially below the melting area.

6. The invention according to claim 1, and

shield means including a plurality of upper coolant spray shield portions in the rammed refractory material and said injector means including a plurality of injectors each being surrounded by a respective shield portion, and

said shield means including a lower portion and a coolant drain reservoir shrouded thereby for receiving coolant from the spray area between the shields and theinjectors.

7. The invention according to claim 6, and

grid means over said reservoir for allowing draining of the sprayed coolant into the reservoir.

8. The invention according to claim 2, and

said bottom wall being a metal plate and said shield means including a plurality of tubes pressed into said plate with openings in the plate each communicating with a respective tube interior and said injectors each being within a respective tube.

9. The invention according to claim 2, and

said converter having a pair of trunnions and trunnion support standards connecting with said trunnions and pivotally supporting saidconverter and coolant conduit means extending through said trunnions and connecting with said cooling means for supplying coolant from an outside source.

10. In a bottom-blow steel making converter, a converter-bottom comprising:

a metal shell side wall means,

a metal bottom wall,

gas injector means extending upright through the bottom wall,

rammed refractory material between the injector means and the'side wall means and forming a bottom surface below a converter melting area up to which extends a top of the injector means to provide gaseous communication of the gas within the injector means into the interior of the melting area.

coolant spray and metal shield means between the refractory material and the injector means,

coolant spray means extending in between the shield means and the injector means and being below the converter bottom surface below the melting area. said spray means spraying the coolant under low pressure in the area of the injector means attendant to cooling the gases to be emitted from the injector means,

cooling means between the injector means and the metal sidewall means in the rammed refractory material and spaced substantially below the bottom surface of the melting area so as not to come in contact with the melting area,

said injector means comprising a plurality of injectors within the rammed refractory material, each injector including a pair of concentric inner and outer tubes defining a central inner passageway communicating with the interior of the melting area and an outer annular passageway surrounding the central passageway and communicating with the interior of the melting area, the outer tube having an upper part,

said outer passageway providing for a conduit of a protective gas such as methane and the inner passageway providing a conduit for oxygen gas,

said metal shield means being spaced substantially below the melting area,

said metal shield means being spaced from and disposed annularly around said spray means and said outer tube of the injector, and

a tapered and top annular metal collar means being over and connecting with said shield means, and having a reduced upper end adjacent the bottom surface of said refractory material and an enlarged lower end disposed on said metal shield means, said refractory material including portions surrounding and covering the upper reduced end of said collar mean, said metal collar means being disposed about the upper part of said outer tube whereby said metal collar means and said metal shield means effectively cool the top of said injector means upon operation of said spray means during use of said converter.

11. A water-cooled converter-bottom of the con struction of claim 1, further characterized by the provision of thermal sensitive elements embedded at various depths in the refractory material to measure the temperature gradient through the converter-bottom for regulating the degree of cooling of the bottom wall by water spray.

12. A water-cooled converter-bottom as described in claim 1 and further characterized by the provision of a protective shroud located under the converter-bottom housing, the coolant spray means and the gas injector means and a water basin for collecting the spray coolant.

13. A water-cooled converter-bottom as described in claim 1, and said gas injector means being concentric tube injectors each including an inner oxygen tube and including and outer shield gas tube, a plurality of feeder blocks, each concentric-tube injector being connected to a feeder block, and each feeder block being connected to associated gas supply lines. 

1. In a bottom-blow steel making converter, a converter-bottom comprising: a metal shell side wall means, a metal bottom wall, gas injector means extending upright through the bottom wall, rammed refractory material between the injector means and the side wall means and forming a bottom surface below a converter melting area up to which extends a top of the injector means to provide gaseous communication of the gas within the injector means into the interior of the melting area, coolant spray and metal shield means between the refractory material and the injector means, coolant spray means extending in between the shield means and the injector means and being below the converter bottom surface below the melting area, said spray means spraying the coolant under low pressure in the area of the injector means attendant to cooling the gases to be emitted from the injector means, and cooling means between the injector means and the metal side wall means in the rammed refractory material and spaced substantially below the bottom surface of the melting area so as not to come in contact with the melting area, said metal shield means being spaced from and disposed about said spray means and said injector means, and a tapered and top annular metal collar means having a reduced upper end adjacent the bottom surface of said refractory material and an enlarged lower end disposed on said metal shield means, said refractory material including portions surrounding and covering the upper reduced end of said metal collar means from the converter melting area, said metal collar means being disposed about the top of said injector means whereby said metal collar means and said metal shield means effectively cool the top of said injector means upon operation of said spray means during use of said converter.
 2. The invention according to claim 1, and said injector means comprising a plurality of injectors within the rammed refractory material, each injector including a pair of concentric inner and outer tubes defining a central inner passageway communicating with the interior of the melting area and an outer annular passageway surrounding the central passageway and communicating with the interior of the melting area.
 3. The invention according to claim 2, and said outer passageway providing for a conduit of a protective gas such as methane and the inner passageway providing a conduit for oxygen gas.
 4. The invention according to claim 2, and said injector comprising a connecting block to a source of protective gas for the outer tube and to a source of oxygen gas for the inner tube, said block having a first inlet opening for the protective gas and a second inlet opening for the oxygen gas. said block having a first enlarged aperture transverse to and communicating with the first opening and connecting with outer tube, and said block having a second reduced aperture transverse to and communicating with second opening and connecting with the inner tube.
 5. The invention according to claim 1, and said metal shield means being spaced substantially below the melting area.
 6. The invention according to claim 1, and shield means including a plurality of upper coolant spray shield portions in the rammed refractory material and said injector means including a plurality of injectors each being surrounded by a respective shield portion, and said shield means including a lower portion and a coolant drain reservoir shrouded thereby for receiving coolant from the spray area between the shields and the injectors.
 7. The invention according to claim 6, and grid means over said reservoir for allowing draining of the sprayed coolant into the reservoir.
 8. The invention according to claim 2, and said bottom wall being a metal plate and said shield means including a plurality of tubes pressed into said plate with openings in the plate each communicating with a respective tube interior and said injectors each being within a respective tube.
 9. The invention according to claim 2, and said converter having a pair of trunnions and trunnion support standards connecting with said trunnions and pivotally supporting said converter and coolant conduit means extending through said trunnions and connecting with said cooling means for supplying coolant from an outside source.
 10. In a bottom-blow steel making converter, a converter-bottom comprising: a metal shell side wall means, a metal bottom wall, gas injector means extending upright through the bottom wall, rammed refractory material between the injector means and the side wall means and forming a bottom surface below a converter melting area up to which extends a top of the injector means to provide gaseous communication of the gas within the injector means into the interior of the melting area, cooLant spray and metal shield means between the refractory material and the injector means, coolant spray means extending in between the shield means and the injector means and being below the converter bottom surface below the melting area, said spray means spraying the coolant under low pressure in the area of the injector means attendant to cooling the gases to be emitted from the injector means, cooling means between the injector means and the metal side wall means in the rammed refractory material and spaced substantially below the bottom surface of the melting area so as not to come in contact with the melting area, said injector means comprising a plurality of injectors within the rammed refractory material, each injector including a pair of concentric inner and outer tubes defining a central inner passageway communicating with the interior of the melting area and an outer annular passageway surrounding the central passageway and communicating with the interior of the melting area, the outer tube having an upper part, said outer passageway providing for a conduit of a protective gas such as methane and the inner passageway providing a conduit for oxygen gas, said metal shield means being spaced substantially below the melting area, said metal shield means being spaced from and disposed annularly around said spray means and said outer tube of the injector, and a tapered and top annular metal collar means being over and connecting with said shield means, and having a reduced upper end adjacent the bottom surface of said refractory material and an enlarged lower end disposed on said metal shield means, said refractory material including portions surrounding and covering the upper reduced end of said collar mean, said metal collar means being disposed about the upper part of said outer tube whereby said metal collar means and said metal shield means effectively cool the top of said injector means upon operation of said spray means during use of said converter.
 11. A water-cooled converter-bottom of the construction of claim 1, further characterized by the provision of thermal sensitive elements embedded at various depths in the refractory material to measure the temperature gradient through the converter-bottom for regulating the degree of cooling of the bottom wall by water spray.
 12. A water-cooled converter-bottom as described in claim 1 and further characterized by the provision of a protective shroud located under the converter-bottom housing, the coolant spray means and the gas injector means and a water basin for collecting the spray coolant.
 13. A water-cooled converter-bottom as described in claim 1, and said gas injector means being concentric tube injectors each including an inner oxygen tube and including and outer shield gas tube, a plurality of feeder blocks, each concentric-tube injector being connected to a feeder block, and each feeder block being connected to associated gas supply lines. 